Friction driving gear for motor vehicles



G. S. MEPSTEAD. FRICTION nmvms GEAR ron MOTOR VEHICLES.

APPLICATION FILED JAN. 3| 192l- Patented Aug. 1, 1922.

2 SHEETS-SHEET MENTOR G. S. MEPSTEAD. FRICTION DRIVING GEAR FOR MOTORVEHICLES.

APPLICATION FILED JAN. 3.1921.

MENTOR. GEmeESmNEYMmm/m PER-'- ATTORNEYS.

UNITED STATES GEORGE SIDNEY MEPSTEAD, OF MORTLAKE, LONDON, ENGLAND.

FRICTION DRIVING GEAR FOR MOTOR VEHICLES.

Specification of Letters Patent.

Patented Aug. 1, 1922.

Application filed January 3, 1921. Serial No. 434,715.

To all wiwm it may concern:

Be it known that I GEORGE SIDNEY ME?- STEAD, subject of the king ofGreat Britain and Ireland, residing at 26 Second Avenue, Mortlake, inthe county of London, England, have invented certain new and usefulImprovements in Friction Driving Gears for Motor Vehicles, of which thefollowing is a specification.

This invention relates to apparatus for the transmission of power fromthe engine to the road wheel or wheels of motor vehicles andparticularly to motor-cycles.

According to this invention I provide a suitably shaped conical frictiondisc mounted upon the wheel 01' wheels to be driven. Upon suitableguides on the vehicle frame arranged parallel to the face of thefriction disc upon the driven wheel, is mounted a suitable slidablecarriage adapted to carry the driving wheel. The driving wheel isconical in form and mounted upon a suitable short shaft adapted torotate in bearings in a bracket supported upon the slidable carriage.

The axis of the shaft and the conical friction wheel is arrangedsubstantially at right angles to the axis of the conical friction plateupon the wheel to be driven, and the bracket is slidably supported uponthe car- .ria e and acted upon by suitable springs which force it-in alateral direction so as to press the friction wheel into contact withthe friction disc.

1 .A suitable telescopic shaft connects the of the shaft carrying thefriction wheel to a short shaft adapted to be driven by the engine ofthe motor vehicle, either direct or through any suitable gearing. Thetelescopic shaft is connected at each end through the medium of suitableflexible or universal joints so as to allow of relative movement betweenthe shaft carrying the friction wheel and the shaft driven by theengine, whilst the telescopic connection enables the carriage upon whichthe friction wheel is mounted to be slidden along its guides so as totraverse the friction wheel across the face of the friction disc so asto vary the gear ratio at which the drive is transmitted be tween them.

The friction wheel may be mounted upon the end of its shaft b means of asuitable helical screw-threade connection, so that the driving torquetransmitted from the shaft to the friction Wheel will cause the latterto slide upon the shaft against the action of a spring and so tend toincrease the pressure between its surface and the surface of thefriction disc in proportion to the driving torque to be transmitted.

Suitable actuating levers or other control mechanism are provided toenable the sliding carriage to be moved along its guides so as to varythe effective gear ratio between the driving wheel and the driven disc.A suitable Bo'wden wire or othercontrol is provided toenable the bracketcarrying the friction wheel to be drawn away from the face of thefriction disc against the action of the spring or springs so as torelease the pressure between the face of the driving wheel and thedriven disc so as to produce a clutching effect, enabling slip to beobtained between the driving wheel and driven disc, or to disengage themwholly so as to obtain a free engine.

In order that my invention may be more readily understood reference ismade to the accompanying sheet of illustrative drawings in which Fig. 1is a side elevation of a convenient construction of m apparatus fortransmitting power as app ied to a motor-cycle.

Fig. 2 is a plan of same.

F ig. 3 is an end view of the slidable carria e carrying the frictionwheel, and;

ig. 4 is a lon itudinal section through the driving whee showing amethod of mountingit upon its shaft.

Referring to the drawings the conical friction disc 1 is mounted uponthe driven wheel 2 of the motor-cycle concentrically with its axis. Aslidable carriage 3 is mounted upon the chain stays 4 of the motor-cycleso that it may be moved longitudinally on these chain stays which form,and are hereinafter referred to as guides, and are arranged parallel tothe conical face of the friction disc 1. The slidable carriage I? isprovided with a'series of guide pins or rods 6, projecting transverselyfrom its face toward the surface of the driven disc 1 upon the wheel 2of the motor-cycle. On these guide pins 6 is mounted a bracket 7, inwhich is journalled a short shaft 8 carryinn at one end the conicaldriving wheel 9, mid connected at its other end to the source of power.

The method of connecting the shaft 8 to the source of power is by meansof a telescopic shaft arranged in two sections 10 and 11, the former ofwhich is connected by a universal joint 12 to the shaft 8, whilst thelatter is connectedhy a universal joint 13 to a short shaft trimmed inhearin 15 upon the crank case of the engine. TlllS shaft l i is providedWith a bevel wheel 16 which gears with an tlier bevel wheel 17 upon theshaft of the engine so that the short shaft 14; will be driven directfrom the engine through bevel wheels 16 and 17 and sincethis shaft 14 isconnected by the telescopic. haft 10 and 11, and universal joints 12 and13 to the shaft 8, the conical driving wheel 9 mounted upon the end ofthis shaft -w-illbe driven by the engine at a suitable speed The axis ofthe shaft 8 carrying the conieal driving wheel 9 is arran edsubstantially upon a line which is r 1a1 from a the centre of the drivendisc 1 so as to main- 20w-taina true drivi contact between the drivingwheel ,9 and tfie disc 1 at any osition.

Whilst/the guides tupon Wlllcl the carriage 3 slides are arrangedparallel to the conical surface of the driven disc 1, the axis 0f theshaft 8 carrying the driving Wheel 9 {is arranged Substantial 1y atright angles to rtheaxis o'f; the driven, disc 1 and the wheel 2 01? themotor-cycle. This enables a driving wheel 9 of considerable Width to beempl oyed, Whilst allowing a true engagement ialonglrits Whole width tobe maintained with -tlie driven disc 1.

The bracket 7, in which the shaft 8 is nnounteicl, mayslide upon thelateral guide ipins6, and a coil spring 18 is arranged betweentheslidable carriage 3 and the bracket 7 so as to tend to forcethe bracket7 along its guide pins 6 toward the driven disc 1, tbtisholding thedriving Wheel 9 into fric- 4qtional engagement with the surface of the'ffi'disc 1.. .1 r r v A suitable connectionlli passes through a 7 boss20, upon the carria e 3. This is adapted mtofirawe back the brac et 7 a'ainst the ac :tion of the spring 18 and so; re ieve the pres surebetween the driving wheel 9 and the disc, 1,. or to entirely disengagethem so as to .;provide a free engine.

Referringnow more particularly to Fig. 4,;which shows the method ofmounting the drivin -,n'heel 9'upon its shaft 8, the outer ,end 0 the;latter. is provided with a helical screw-threadQ-l of steep pitch. Theconical driving Wheel 9 which is built up of suitable uiaterial'having ahigh co-efiicient of friction; is provided with a metal bush 22 in whichis cut a helical screw-thread 23, whi -h corresponds and engages withthe sch-u: A thread 21 upon the shaft 8. In the outer end of the bush 22is PXOYldeul a recess 24- in which engages a coil spring 25,'the otherend of which bears against the *washer 26 and nut 27 upon the end of [heshaft, This spring 25 will thus lend to force the friction Wheel 9 on toits shaft and said hearing, a conical ed upon said short fs'haft, dpring'rtie'ansinaway from the axis of the driven disc 1. When, however, poweris being-transmitted, the direction of rotation of the shaft 8 and theangle of the helical screw-thread 21 upon its end are such that thedriving wheel 9 will be forced along its shaft 8 against the action ofthe spring 25 and toward the centre o'f thedriven disc 1.

Owing to the conical nature of this driving wheel 9 and the driven disc1, this will cause an incrcase in the effective pressure between thesurface of the wheel 9 and the disc lso as to increase thefrictionbetween them and ensure an 'e'fiecti've transmission of the ower.

As he power to be transmitted, or the force to be overcome increases,the wheel 9 will be screwed further alongitssliaft '8 so that thefriction between it a d the disc 1 will increase in proportion.

I cla'iinzl. A d-r'iving gear for Tnotor vehicles comprising a vehicleframe havinga ri' id part, a driven wheel, a conical driven iscconnected to saiddriven Wheel, a driving shaft, a conical drivin memberslidably mounted upon said driving shaft, a carriage adapted to supportsaid drivingmember slidalo'ly mounted u'pon'said ri id part of'thevehicle frarne whereby, the effective gear ratio they be vari'ed,andr'nea'ns forbrin'g'ing increased pressure upon the driven di'scduringfr'otm tion of said'driving shaft, said carriage being providedwith means relatively mjovable therein :wher'ebyfsaid drivingi'n'en'ib'er' ma be brought into tr out'of engaghint wit the drivendisc.

I 2. drivin gear for n'iotor vehicles,'coinprising 'adriven wheel, aconicaldriven disc coiinectedjto'said driven wheel, a lori itiidina'llyslid'able carriage, guideipins'carried'by said carriage. a bearings-lidably niodiited upon said guide pins for lateral 'niovenientiritl'iiii said carriagma short shaft carried in rivingw'heeltriolintterposed between said bearing and chrr'agewhereby;thedrivin wheel is maintains 1n tone-ar na; the diiv'en disc,Said bearing being movaljle "upon said "guide pins against the'uct'ionof said spring, whereby the driving wheel may be brought bill;of contact with the driven disc.

3. A driving gear for motor vehicles, comprisin a driven wheel, aconical driven'disc connected to said driven wheel, a longitudiuullyslidable carriage, a liearing'laterally movable within said carriage. ashort shaft married in said bea'ring, a conical driving wheel mountedupon said short sh'a ft,a tele scopic shaft cdnneti 'g'said short shaftwith the engine, aduick pitch screw thread on said short shaft, :1corresponding thread in the interior of the driving wheel with which itengages so that the rotation of the shaft will tend to force the wheeltoward the axis of the driven disc, a spring upon the shaft tending toforce the wheel in the reverse direction, rigid guides upon which thecarriage is supported so that the bearing of said shaft may slideparallel to the conical face of the driven disc, transverse guides uponing wheel in frictional contact therewith.

GEORGE SIDNEY MEPSTEAD.

